Debian

Debian is a Linux release, which is preffered for desktop computers, but it has been becoming more popular as a server OS over the last few years as well. It's very stable and secure, as fixes are released within a few days after an issue is discovered. Debian has a huge support community, so if you have any questions or issues with the OS or with some of the 30,000+ packages it features, you can contact the developers immediately via e-mail using special mailing lists and receive a reply within 15-20 minutes. The Debian community gives you the best level of support possible, since all your questions will be handled by exactly the same people that built Debian in the first place, so they have an exhaustive knowledge of how their system works. As the Operating System is 100% free to use and distribute, no license costs will be added to your website hosting fees and you will be able to modify the code files and any other software which you install with no restrictions, to optimize the software environment for your Internet sites. Furthermore, Debian performs very well on any kind of hardware, as it is light and fast and doesn't require a lot of memory.